Failure processes of cemented granular materials

Area of Science:

• * Physics of granular materials
• * Material science and mechanics
• * Computational modeling

Background:

• * Cohesive granular materials exhibit complex mechanics due to heterogeneous granular responses and defined material properties.
• * Understanding the link between microscopic particle interactions and macroscopic material behavior is crucial.

Purpose of the Study:

• * To explore deformation and failure mechanisms of cohesive granular materials under uniaxial compression.
• * To establish a connection between microscopic interactions and macroscopic material response.
• * To develop a unified framework for understanding porous material failure.

Main Methods:

• * Discrete element model (DEM) simulation of elastic particles connected by breakable elastic bonds.
• * Particle and bond properties matched to experimental measurements of cohesive granular media.
• * Bond breakage criterion based on Griffith energy balance with realistic surface energies.

Main Results:

• * The model reproduces a wide range of experimental behaviors, including elastic and post-elastic responses.
• * Accurate prediction of distinct failure modes: shear-banding, ductile failure, and compaction banding (anticracks).
• * Demonstrated transitions between different failure modes based on initial volume fraction.

Conclusions:

• * The discrete element model provides a unified framework for understanding cohesive granular material failure.
• * The model's success in predicting diverse failure modes validates its approach.
• * Applicable to various porous materials like sandstone, marble, snow, and foam.